Subconjunctival dexamethasone implant lowers risk of graft rejection after penetrating keratoplasty
Subconjunctival dexamethasone implant may be a safe and well-tolerated immunosuppressive therapy for patients after low-rejection risk penetrating keratoplasty suggests a new study published in the British Journal of Ophthalmology
Rejection is the main cause of graft failure after penetrating keratoplasty (PK). Its prevention by repeated instillation of steroid eye-drops has not evolved in decades. Poor adherence and discontinuous nature of eye-drop treatment may explain some PK failures. In a rabbit model, we previously demonstrated that a subconjunctival dexamethasone implant was well tolerated and prevented rejection efficiently in the first 5-6 weeks. This clinical trial investigates its tolerance and safety after PK.
Single-centre, phase II non-randomised tolerance and safety pilot study (NCT02834260). Designed to analyse the risk of elevated intraocular pressure (IOP), discomfort and resorption time. Fourteen patients with a low rejection risk indication of PK were enrolled between January 2017 and August 2018. The implant was injected in the 12 o'clock position, 5 mm from the limbus, at the end of PK. A steroid eye-drop treatment was planned when implant resorption was complete. Patients were monitored regularly for 12 months: IOP (main outcome measure at 1 month), discomfort and redness scores, implant status, rejection episode and central corneal thickness by optical coherence tomography. An independent data safety monitoring committee verified safety aspects.
Results:
No increase in IOP or other adverse event related to the implant was observed. Average resorption time was 6 weeks. The switch to steroid eye-drops was uneventful. One patient, included despite preoperative corneal neovascularisation (unintended protocol deviation) experienced a rejection.
This is the first proof of concept that dropless immunosuppression is possible after low rejection risk PK.
Reference:
Trone MC, Poinard S, Crouzet E, Garcin T, Mentek M, Forest F, Matray M, Thuret G, Gain P. Dropless penetrating keratoplasty using a subconjunctival dexamethasone implant: safety pilot study. Br J Ophthalmol. 2023 Feb;107(2):181-186. doi: 10.1136/bjophthalmol-2021-319376. Epub 2021 Aug 23. PMID: 34426402.
Keywords:
British Journal of Ophthalmology, Subconjunctival, dexamethasone, implant, safe, well-tolerated immunosuppressive, therapy, patients, low-rejection, risk, PK, Trone MC, Poinard S, Crouzet E, Garcin T, Mentek M, Forest F, Matray M, Thuret G, Gain P.
